Richard Webby, PhD, is also the Director of the World Health Organization’s Collaborating Center on the Ecology of Influenza in Animals and Birds that focuses on understanding influenza and improving vaccines to combat the virus. He is also a faculty member at St. Jude Children's Research Hospital.

Dr. Richard Webby, a member of the infectious disease department at St. Jude Children's Research Hospital, says this season has been more mild, but even a mild flu season can lead to a lot of illness—-and even death.

Dr. Webby reveals how effective this year's flu vaccine is and if it's worth getting. He also discusses new research that suggests the lifespan of the flu shot may be shorter than experts once thought—should you get a second vaccine later in the season?

Plus, learn the doctor-recommended ways to prevent the flu including washing your hands and avoiding people who are sneezing and coughing.